package demo1;
import java.util.Scanner;
public class Test1 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        while (input.hasNextLine()) {
            String s = input.nextLine();
            if (!((s.length() >= 1 && s.length() <= 100) && isletters(s))) {
                break;
            }else {
                int i = 0;
                int[] arr1 = new int[30];//记录大写字母
                int[] arr2 = new int[30];//记录小写字母
                int index = s.length();
                char[] str = s.toCharArray();
                while (i < s.length()) {
                    if (isfun(str[i]) == -1) {  //判断是大小写
                        arr2[str[i] - 97]++;
                        if (arr2[str[i] - 97] == 1) {
                            System.out.print(str[i]);
                        }
                    } else {
                        arr1[str[i] - 65]++;
                        if (arr1[str[i] - 65] == 1) {
                            System.out.print(str[i]);
                        }
                    }
                    i++;
                }
                System.out.println();
            }
        }
    }
    public static boolean isletters(String s) {
        int i = 0;
        char[] arr = s.toCharArray();
        while (i < s.length()) {
            if ((arr[i] >= 'a' && arr[i] <= 'z') || (arr[i] >= 'A' && arr[i] <= 'Z')) {

            }else {
                return false;
            }
            i++;
        }
        return true;
    }
    public static int isfun(char ch) {
        if (ch >= 'a' && ch <= 'z') {
            return -1;
        } else {
            return 1;
        }
    }
}
